Here's a trick which MAY be useful. Like all the best ideas, I discovered it
by accident - in this case while trying to print an envelope short side in.

If you cut a sheet of paper to less than a certain length (the exact length
will vary with your printer) and feed it to a laser printer, then the feed
rollers after the toner deposition stage will (may?) fail to pick it up and
the paper will stop in the midst of the printer without having been fused.

I have an old HP4L that I normally use and if I feed it a half sheet it sits
nicely in the printer until I remove the toner cartridge and take it out.
You now have an unfused smudge free copy waiting to be transferred to
something else.

I haven't tried this for PCB work but I have used it to transfer toner to
mugs and then baked them in a domestic oven to produce a surprisingly robust
finish.
I have also transferred pictures from a scanner to a plastic surface by this
method.
YMWV

This would be very easy for someone to try for PCB purposes - if you do
please let us know the results!

You could perhaps get a similar result by depowering the fuser roller (or
removing it ?) but this would be much harder to do and much more liable to
smudge.